Stmicroelectronics (shenzhen) R&d Co. Ltd.

Stmicroelectronics S.r.l.

Emerson Network Power, Energy Systems, North America, Inc.

Vertiv Energy Systems, Inc.

XiangSheng Li

Mei Yang

Cristiano Meroni

Ru Feng Du

Xian Feng Xiong

Liwei Huang

Feng Xu

Kelvin Jian Wen

Yaming Shi

YueHua Wang

Xaut Zhang

Yuangang Liu

Xianfeng Xiong

GuoHua Zhong

An audio amplifier includes: a buck controller configured to control an output voltage at a first supply terminal, the output voltage selected from a set including a plurality of output voltages, where the output voltage takes a settling time to settle; a first audio bridge including: a class-AB driver stage coupled to the first supply terminal, and a delay insertion circuit configured to receive a processed digital stream and provide the processed digital stream to the class-AB driver stage a delay time after receiving the processed digital stream, where the delay time is based on the settling time; and an audio amplitude detector configured to detect a first peak amplitude in the first digital audio stream, where the buck controller is configured to select a lowest output voltage from the set that is higher than the first peak amplitude plus a headroom voltage.

Audio amplifier with embedded buck controller for class-G application

In an embodiment, a class-AB amplifier includes: an output stage that includes a pair of half-bridges configured to be coupled to a load; and a current sensing circuit coupled to a first half-bridge of the pair of half-bridges. The current sensing circuit includes a resistive element and is configured to sense a load current flowing through the load by: mirroring a current flowing through a first transistor of the first half-bridge to generate a mirrored current, flowing the mirrored current through the resistive element, and sensing the load current based on a voltage of the resistive element.

Advanced load current monitoring circuit and method for a class-AB amplifier

There is provided a transformer including an E shaped and two I shaped magnetic cores and a first, second and third windings, wherein: one I shaped magnetic core is located between one side and a middle legs of the E shaped magnetic core, another is located between another side and the middle legs; there is an air gap on each of the two I shaped magnetic cores or two side or bottom legs of the E shaped magnetic core, the first winding is wound on a part of the magnetic cores where the air gap exists; the second and third windings are wound on the middle leg; and the first winding is connected in parallel with the second winding to constitute a primary winding; the third winding is a secondary winding. With the transformer provided by the disclosure, transformer winding loss can be reduced, and transformer efficiency can be improved.

Transformer

A circuit can be used in a speaker system. The circuit includes an amplifier with an output configured to be coupled to a speaker. An offset comparator has an input coupled the output of the amplifier and is configured to provide an offset control signal. A digital circuit has a first input coupled to an output of the offset comparator, a second input configured to receive an amplifier control signal, a third input configured to receive a play control signal, and an output configured to provide a forced mute signal that can be used to control the amplifier.

Embedded speaker protection for automotive audio power amplifier

A digital circuit can be used in a speaker system. An intermediate node provides a speaker protection control signal. A first latch for receives an offset control signal. A first logic gate receives a play control signal, the offset control signal, and the speaker protection control signal. A second logic gate is coupled to the first latch for receiving the play control signal and the speaker protection control signal. A second latch is coupled to the first logic gate for providing a forced mute signal. A third latch is coupled to the second logic gate and to the intermediate node.

A method of operating a speaker system including a speaker coupled to an amplifier, and a dedicated digital speaker protection circuit includes turning on the amplifier in a mute mode, after a first delay period, issuing a play command to the amplifier to place the amplifier in a play mode, but without an input signal during a second delay period, and performing a speaker offset detection during the second delay period, wherein, if there is an offset, then the amplifier is forced back into the mute mode, and if there is no offset, then the amplifier is allowed to continue to operate in the play mode. The method also includes issuing a speaker protection control signal or command if an offset is detected.

A clamping circuit for a class AB amplifier includes a reference voltage circuit, four NPN Darlington transistors having inputs coupled to the reference voltage circuit, and outputs for providing four clamped voltages and a split NPN Darlington transistor having an input coupled to the reference voltage circuit, and four separate outputs for providing four AC ground voltages.

Input clamping structure for sound quality improvement in car-radio class-AB power amplifier design

There is provided a transformer including an E shaped and two I shaped magnetic cores and a first, second and third windings, wherein: one I shaped magnetic core is located between one side and a middle legs of the E shaped magnetic core, another is located between another side and the middle legs; there is an air gap on each of the two I shaped magnetic cores or two side or bottom legs of the E shaped magnetic core, the first winding is wound on a part of the magnetic cores where the air gap exists; the second and third windings are wound on the middle leg; and the first winding is connected in parallel with the second winding to constitute a primary winding; the third winding is a secondary winding. With the transformer provided by the invention, transformer winding loss can be reduced, and transformer efficiency can be improved.

A clamping circuit for a class AB amplifier includes a reference voltage circuit, four NPN Darlington transistors having inputs coupled to the reference voltage circuit, and outputs for providing four clamped voltages, and a split NPN Darlington transistor having an input coupled to the reference voltage circuit, and four separate outputs for providing four AC ground voltages.

An amplifying circuit includes a first circuit component configured to receive and amplify first and second input voltages to generate an output voltage. The first circuit component is formed by a first amplifier and a second amplifier. A second circuit component is configured to provide a first offset current that is associated with a first input current of the first amplifier. The first offset current compensates for variation in the first input current. A third circuit component is configured to provide a second offset current that is associated with a second input current of the second amplifier. The second offset current compensates for variation in the second input current.

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Shenzhen, China

XiangSheng Li